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- Dell'Elce, Simone, et al.
(författare)
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3D to 2D reorganization of silver-thiol nanostructures, triggered by solvent vapor annealing
- 2018
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 10:48, s. 23018-23026
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Tidskriftsartikel (refereegranskat)abstract
- Metal-organic composites are of great interest for a wide range of applications. The control of their structure remains a challenge, one of the problems being a complex interplay of covalent and supramolecular interactions. This paper describes the self-assembly, thermal stability and phase transitions of ordered structures of silver atoms and thiol molecules spanning from the molecular to the mesoscopic scale. Building blocks of molecularly defined clusters formed from 44 silver atoms, each particle coated by a monolayer of 30 thiol ligands, are used as ideal building blocks. By changing solvent and temperature it is possible to tune the self-assembled 3D crystals of pristine nanoparticles or, conversely, 2D layered structures, with alternated stacks of Ag atoms and thiol monolayers. The study investigates morphological, chemical and structural stability of these materials between 25 and 300 °C in situ and ex situ at the nanoscale by combining optical and electronic spectroscopic and scattering techniques, scanning probe microscopies and density-functional theory (DFT) calculations. The proposed wet-chemistry approach is relatively cheap, easy to implement, and scalable, allowing the fabricated materials with tuned properties using the same building blocks.
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| 2. |
- Miglbauer, Eva, et al.
(författare)
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Synthesis and Investigation of N,N-benzylated Epindolidione Derivatives as Organic Semiconductors
- 2016
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Ingår i: ChemistrySelect. - : WILEY-V C H VERLAG GMBH. - 2365-6549. ; 1:20, s. 6349-6355
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Tidskriftsartikel (refereegranskat)abstract
- We report how the N, N-disubstitution of epindolidione with a benzyl group surprisingly leads to irreversibility of oxidation and thus to only n-type transport in a material with otherwise quasi-reversible reduction and oxidation and charge transport ambipolarity. Cyclic voltammetry, bulk electrolysis and UV-Vis spectroscopic methods were applied to elucidate the electrochemical reaction pathway leading to oxidative degradation and conclude that the same product that can be produced electrochemically is also found in the solid-state device. The chemical substitution of hydrogen-bonded acridone-based semiconductors can lead to substantial changes in their electrical properties, and more broadly, the electrochemistry of organic semiconductors in solution can be closely related to their solid-state charge transport phenomena.
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| 3. |
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| 4. |
- Perchiazzi, Natale, et al.
(författare)
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Gabrielsonite revisited: crystal-structure determination and redefinition of chemical formula
- 2018
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Ingår i: European journal of mineralogy. - : Schweizerbart. - 0935-1221 .- 1617-4011. ; 30:6, s. 1173-1180
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Tidskriftsartikel (refereegranskat)abstract
- A reinvestigation of gabrielsonite from the holotype specimen from Långban, central Sweden, using single-crystal synchrotron X-ray diffraction, electron-microprobe techniques and Fourier-transform infrared (FTIR) spectroscopy, Raman and Mössbauer spectroscopies show that the mineral is an anhydrous Fe3+-bearing arsenite and not a hydrous Fe2+-bearing arsenate, as originally proposed. The revised ideal chemical formula of gabrielsonite is PbFe3(As3+O3)O. The mineral is related to the descloizite supergroup, but it differs through the valencies of the non-Pb cations Fe (M3+ vs. M2+) and As (3+ vs. 4+) and through lower coordination of Pb (4 vs. 7–8) and As (3 vs. 4). The redefinition of gabrielsonite (proposal 17-G) has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association.
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| 5. |
- Weclawski, Marek K., et al.
(författare)
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Biscoumarin-containing acenes as stable organic semiconductors for photocatalytic oxygen reduction to hydrogen peroxide
- 2017
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488. ; 5:39, s. 20780-20788
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Tidskriftsartikel (refereegranskat)abstract
- Conversion of solar energy into chemical energy in the form of hydrogen peroxide and other reactive oxygen species has been predicted to be an efficient strategy, yet few organic materials systems support these types of photochemical conversion reactions. Herein we report a simple synthetic route to yield biscoumarin-containing acenes, semiconducting small molecules with exceptional stability and tunable electrochemical and electrical properties. We find that these semiconductors are photo(electro) catalysts capable of reducing oxygen to hydrogen peroxide. Visible light irradiation of thin films on insulating substrates in pure water results in H2O2 photogeneration with water as the sacrificial electron donor. Thin films on conducting substrates are robust catalytic photocathodes for producing H2O2. These semiconductor photoelectrodes retain their catalytic properties in a pH range from 2-13. Photocatalytic or photoelectrocatalytic deployment of biscoumarin-containing acenes does not lead to measurable degradation. This work demonstrates a strategy to synthesize stable organic semiconductors not only suitable for thin-film electronic devices but also next-generation photocatalytic concepts.
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